Detergent compositions and, in particular, liquid detergent compositions are well known and widely used. Typical applications include dish detergents, hand cleaners, car washes etc. Liquid detergents have met with a high degree of acceptance primarily because of their good cleaning and convenient form for use, among other things.
Many detergent compositions, such as liquid hand dishwashing detergents, consist of two major fundamental components, a surfactant base and a foam booster. The surfactant base, which usually consists of one or more anionic and/or optionally nonionic surfactants, is largely responsible for the foam profile, i.e., initial copious foam height, volume and density, and cleaning performance of dish detergents.
Liquid dish detergents can contain specific types of surfactants which are known to be more effective at removing certain specific types of soils. For example, anionic surfactants are known for their ability to remove carbohydrate and protein type soils, while nonionic surfactants are especially useful in removal of greasy and oily food prep soils. Mixtures of surfactants are commonly used to clean and remove complex soil types which can be found on dishes and kitchen utensils.
In liquid hand dishwashing detergent compositions, consumers often associate thick and viscous products with high performance because of the natural inference that viscous products are more concentrated than non-viscous products. Thus, viscosity infers concentrated product which suggests higher quality and performance.
Additionally, for many detergent compositions, particularly liquid dish detergents, performance is normally evaluated by the consumer in terms of foaming and foam stability. The consumer associates better product performance with the presence of higher levels of foam or suds and by foam that lasts for extended periods of time even when exposed to various food preparation soils. Dish detergent compositions presently on the market are designed to remove oily/greasy soils from glasses, dishes and other tableware and kitchen utensils while maintaining an acceptable layer of foam or suds. Consequently, there is an ongoing search to make detergent compositions that clean and foam better, and produce a more stable foam.
Foam boosters, which are also known as foam stabilizers or suds enhancers are commonly used to prolong the life, i.e. existence or presence, of the foam head generated during the dishwashing process. Hand dish detergents are expected to produce copious amounts of foam in the presence of a variety of food prep soils. Foam boosters provide the abundant long-lasting foam that consumers perceive as being directly proportional to detersive ability.
The stabilized foam head of these hand dish detergent compositions is created by agitation of the surfactant. Such detergent compositions are intended for use in manual cleaning operations and are not intended for use in automated washing processes where the copious foam produced by the agitation would interfere with the automated cleaning process.
In addition to producing abundant foam and extending foam life, foam boosters typically provide other beneficial properties to hand dish compositions. Traditionally, they are known as specialty multifunctional components. For instance, as mild surface active agents, they enhance the cleaning performance of hand dish detergents, and greatly impact the aesthetic appeal of the detergent composition through viscosity modification and emolliency. Typically, the act or process of hand washing dishes exposes one's hands to the detergent ingredients for a prolonged period of time. Therefore, great emphasis is placed on the testing and selection of mild non-irritating components. Low skin irritation as well as the overall postwashing skin condition of user's hands is a concern to commercial formulators. Detergent compositions with strong acids and bases that create pH conditions which would irritate or injure the user are not acceptable for use in hand washing operations. Further, these detergent products are intended for use at mild temperatures (i.e., in the range of 28-47.degree. C.) which would not irritate or injure the user.
Typical foam boosters such as amine oxides, betaines, sultaines and alkanolamides have been shown to be mild ingredients and are widely used in liquid dish detergents today. Often, certain of these foam boosters exhibit solubility problems, present handling difficulties, and result in less than optimum detergent compositions.
Because of the consumer perception that certain high sudsing or foaming detergent compositions provide better cleaning, there is an ongoing search in the art to continuously improve sudsing and foaming of detergent compositions in the presence of various soils, particularly soils including carbohydrates, proteins and fats typically associated with food. Further, there is an ongoing search to provide new milder, more efficient and cost effective foam boosters.